Andrew_B

If you're using a binoviewer is there any advantage to using a tele extender over a standard Barlow lens or does it not matter?

I wear glasses but take them off when I'm observing and I've adjusted fairly easily to using my 6mm ortho, although it did seem a bit strange at first and I have poked myself in the eye a couple of times! 🤣

I recently got a cheap binoviewer which should also be ideal for high magnification observing. I've not had a chance to try it out on any celestial targets with the recent weather but I've done a bit of birdwatching and was impressed by how easy and comfortable it was to use.

29 minutes ago, Merlin said:

I recall reading somewhere that a good Newtonian reflector is superior to any folded-beam instrument.

It's a sweeping statement to say that one design is unequivocally better than the other and they all have their strengths and weaknesses. The ideal scope would probably be an unobstructed three-mirror anastigmat but there are currently no commercially available telescopes of this type.

A Newtonanian can't be as well corrected as two or three-mirror designs without additional optics but for planetary observing things like off-axis coma isn't a major problem so designs like the Newtonian and the Dall-Kirkham work very well. Having two or more curved mirrors has its advantages but it can also make the scope more sensitive to collimation errors and harder to collimate. At a given price point you'll also get a bigger and/or better instrument with a Newtonian due to its simplicity and in long focal ratio models the mirror is relatively easy to fabricate well and allows for a small secondary which is an advantage, especially for the planetary observer.

18 hours ago, Martthebass said:

Following.  Seriously considering upgrading my current GT71 set up to this.  Am I right to assume that the flattener/reducer threads into the back end in the same way as on the GT71?

According to FLO it screws onto the end of the focuser with an M63 x1 thread by the looks of it.

14 hours ago, Stu1smartcookie said:

Unfortunately only 1 available at present , might have to go the ADM route , I certainly want another clamp for the other side of the SkyTee ... ( then i can justify another scope 😀)

I bought something similar through Aliexpress and looking on there now there are a few sellers offering that same basic item for less than £25 including shipping.

I don't think you'd be disappointed by the X-T3. I love the Fuji cameras and even though mine are very basic things like the out of camera JPEGs can be superb. Granted that's not relevant to astrophotography but I think there's a lot to be said for a simplified workflow for normal photography and there's nothing to stop you shooting raw as well to give you more post-processing options if you want something different from what the camera itself has done.

I'm sure the Pentax would be an amazing camera but I don't think full frame is necessary for good AP and it brings additional costs that you might not want to pay. Like you say, it's a much heavier camera so you're losing much of the advantage of APS-C mirrorless which allows for very small and light cameras that don't stress focusers or mounts all that much. The other thing is that while plenty of lenses and telescopes will produce a good image across the 29mm diagonal of an APS-C sensor, you'll find a lot of them aren't suitable for the larger 43mm diagonal of full frame. You see this particularly with things like focal reducers which often only quote a 30-40mm image circle and outside that you get severe vignetting or very visible aberrations.

I wouldn't worry too much about trying to get one perfect camera at this point - you want something that will work well and you'll enjoy using but there's no reason why you can't upgrade or add another camera at a later date that might be better suited for astro. Focusing on learning how to image and your processing workflow will deliver amazing results from even very low end gear but even the best camera is going to produce disappointing results if your processing skills aren't up to much.

I think you'd enjoy the X-T3 and so long as your stacking software handles the raw format (Astro Pixel Processor for example works just fine) I think you'll be impressed by its all-round qualities.

28 minutes ago, johninderby said:

The American made Celestron SCTs were variable in optical quality. Since shifting production to China optical quality seems to be very consistent. Think it has more to do with no longer toiching up optics by hand but relying on improved machine finishing equipment.

On CN this is a very touchy subject that the Chinese made optics are more consistant than the American made optics. 😁

Indeed. They don't make 'em like they used to ... thank goodness! 😆

Touching up optics and carefully rotating elements into the perfect position is a valid method when you're talking about very high end optics like A-P / Tak / TEC, but if you're doing it with a value-oriented product like an SCT it's more likely to be a way of getting round poor QC and inconsistent manufacturing methods.

12 hours ago, GazOC said:

I've got to admit, Mark. I had a 8 inch LX90 SCT years ago and was never particularly impressed with the planetary views it put up 

Quality control with SCTs seems to have been relatively hit and miss especially years ago, but I get the impression that newer models made by Synta have been much better and you're less likely to end up with a lemon.

Are you wearing glasses and does the spike position change as you rotate your head?

10 hours ago, Ed Galea said:

Many thanks Andrew_B, all your comments are great and very useful.  My camera search has led me to the Fujiflim X-T3 or possibly the newer X-T4.  I believe the X-T4 has better video capabilities which may be useful for planetary photography and I think I read somewhere that it is better in low light?.  What do you and the community think about this camera for astrophotography?   Will I be limiting myself in terms of the scope of lenses I can use?  Hopefully, the Samyang 135 has an X mount adapter as this is one of the lenses I'm thinking about getting.  Any advice welcome.

Thanks again.

Thanks for your kind words.

The X-T3 and X-T4 cameras are brilliant models and would make great all-rounders for astro and normal photography but they're not actually the best Fuji cameras for astrophotography because they perform noise reduction on the raw files which I don't think can be turned off. It's a little bit like what Sony do but nowhere near as aggressive so the impact on your images would be far less, but I've seen posts on dpreview where people have tested this and it does reduce the visibility of faint stars in an image compared to what should be there.

This noise reduction is only implemented in Fuji's X-Trans models and their cheaper cameras that use normal Bayer patterns don't seem to be affected so although it's not a good a camera in terms of all round performance, an X-T100 is in some respects a better choice for astro than the X-T3. It doesn't have as good a screen though, so getting your lenses focused at the start of a session is a bit more fiddly.

I think difference is relatively subtle so it's not like you can't get good astro shots with the more expensive models, just that you don't need to spend that much if astro is your number one priority but if you want a great camera for every use then you'll appreciate the features and handling of the better models.

Samyang lenses are available natively in X mount and you can also get relatively cheap adaptors to fit lenses made for Canon EOS or Nikon F mount onto your Fuji camera.

A nice thing about the Fuji cameras is that their red sensitivity is good enough as standard that you can take really good astro shots without having to mod them first. I've even short H-alpha narrowband with my stock X-T100 and got a surprisingly good result.

54 minutes ago, Ed Galea said:

Many thanks Andrew_B, those links you provided are excellent, very informative in describing the problem.  They suggest that the Sony A6400 also suffers from 'star eater' behaviour, so I guess I'll have to drop SONY from my list of possible cameras.  The quest for the right camera and lens continues.  I might explore Canon and Fuji next.  There is so much to learn, which is one of the reasons I like this pursuit so much.

Thanks again for the insight

I'd be happy with either make but I went with Fuji (X-A3 and X-T100) because their red sensitivity out of the box is pretty good and much higher than other makes apart from dedicated astro models.

Canon have the advantage of having a bigger range of lenses, although mirrorless cameras generally work well with older manual lenses of any type. Software to remote control your camera from a PC is also only available for Canon (and Nikon) cameras from what I've seen and adaptors and accessories can be easier to find.

3 hours ago, Ed Galea said:

Thanks Andrew_B, the used camera kit website looks very interesting, I'll definitely have a look at some options on that web site.  Going back to the sony 'star eater' features, how do you know if a camera with the sony sensor has the ability to manually turn off the noise reduction?  Great image by the way.  

Some of the Canon mirrorless cameras look pretty good - the range of lenses available for EOS mount is huge and being mirrorless the shorter flange focal distance means a lot of other lens types can be used with adaptors. The only downside with a stock camera is that most have relatively little red sensitivity and would need to be modified to fully realise their astro capabilities, but that's something you could have done at a later date.

The aggressive noise reduction kicks in when bulb mode is used on some Sony cameras so exposures of 30s or less would be normal. Other models had this behaviour appear with anything over a 4s exposure which isn't very useful. I found some info about the problem here and here.

Thanks for the kind words about the image. I used a mix of 90s exposures for the H-alpha and 120s exposures for the O-III data which would obviously have run into issues with a Sony camera. It's a shame because they're good cameras otherwise.

48 minutes ago, Captain Magenta said:

Shortly after acquiring my LZOS 105/650 f/6.2 scope I tried a direct comparison between my Baader 2” BBHS prism diagonal, and a Revelation 2” dielectric mirror diagonal. I can’t recall the eyepiece I used, but it was the same for both.

I looked at lunar features. With the prism diagonal I could easily see colour-fringes, with the mirror diagonal I could not discern any colour aberration.

Just an extra data-point.

Magnus

 

A 2" prism is apparently more likely to cause noticeable false colour than a 1.25" one, simply because of the extra glass the light has to travel through. If you want to minimise scatter while also keeping false colour to a minimum then a 1.25" prism is the way to go but if you want a 2" model then a good quality mirror is probably the better choice.

I've got that 32mm Baader prism and it's great quality for the money. I felt like I was seeing a little bit more contrast and fine detail compared to my dielectric mirror diagonal but any difference was subtle although the prism has the advantage of being a bit more flexible due to its T-2 connections.

Any laser powerful enough to damage a lens would be far too powerful to use anywhere near unprotected eyes.

One nice thing about the FS-60 in Q mode is that the relatively slow focal ratio is pretty forgiving with eyepieces and even relatively cheap ones like basic Plössls can deliver great views.

If I want a high power zoom I use my Baader Hyperion 8-24mm with the dedicated 2.25x Barlow to give 3.6-10.7mm (56x-159x magnification) since I can't afford the Nagler zoom.

I was using a Barlowed 6mm Fujiyama ortho with my FS-60Q last night to look at the Moon and it was surprising how well the image held up at 225x magnification even in moderate seeing so it's obviously one of those scopes that can take high magnifications very well considering its tiny size.

On 23/10/2021 at 18:15, Highburymark said:

I had a 105mm ETX which was a great lunar scope, and wonderful for quick views - and actually cooldown was pretty rapid too. But you’re not going to see satisfying detail beyond the two main rings on Jupiter for example. The current generation of larger table top Dobsonians look like a much more tempting proposition.

That sounds like a lot less detail than you'd see through a decent 3" refractor. Is the 105mm ETX really that bad?

I like the Hyperion Zoom and I found it looked brighter and more contrasty at the 8mm setting than my 8mm BST Starguider which is a respectable lens in its own right. With the 2.25x Barlow you get a very flexible setup covering 3.6-10.7mm and 8-24mm and I've liked using mine and felt it was good value for money.

Your Skymax is going to be more forgiving of cheaper eyepieces than the 8" GSO due to its longer focal ratio so you might find that even a really cheap Plössl looks good in your Mak but might be a bit disappointing in the Dob.

2 hours ago, badhex said:

I think a lot of astro gear, in particular the things with glass in them, follow something akin to the law of diminishing returns - or what I like to refer to as the "last 5% rule". Audio equipment also follows this rule.

Somewhere in the middle of the quality/cost scale you get a lot of bang for your buck and really see the difference between the low-end and medium to medium-high end, but the differences I think become smaller right at the top five to ten percent.

It's not to say that you don't see those differences, in the ultra high end, because you do usually get what you pay for in astro gear - but it is certainly where you'll spend a huge wad of cash chasing what might end up being a pretty marginal increase. It's just then a question of where to draw the line.

I think you're right.

Something else I've read and tend to agree with is that once you're using reasonable mid-range eyepieces, you'll usually see more of a difference by spending money on a bigger or better scope than you would upgrading your eyepiece collection.

23 hours ago, Ed Galea said:

Hi Andrew_B, many thanks for the comments - this type of information and insight is what I'm looking for!  I hadn't heard of the 'star eater' issue associated with Sony Sensors before.  The Sony A6400 is not a new camera, its from about 2019 so it may suffer from the problem you describe, if so, that is something to be avoided.   However, I thought the Sony CMOS sensors were amongst the best available in standard cameras.  As I mentioned, I don't mind investing a bit of cash in a good camera and lens as I intend to also make use of them for terrestrial photography too.  I'm a bit cautious when it comes to purchasing a second hand camera, as you don't know how they have been handled.  My wife recently dropped her camera and it has had intermittent problems ever since.  But to look at it you think it had just come out of the box!  I'm more relaxed with purchasing a second hand lens rather than a second hand camera body.

The 'star eating' noise reduction behaviour you mentioned for Sony cameras, is it a software or hardware issue?  As many other cameras use Sony sensors I assume it must be a software issue, but if  a software issue, you'd think  you could turn it off through the user interface?   Thanks for the heads up.

Sony sensors are brilliant but the cameras that use them can have image processing pipelines which implement noise reduction or other 'features' which can't be turned off, even when shooting raw. It's a software issue rather than hardware but if the embedded firmware doesn't allow the user to control these settings then you're a bit stuck.

It's a bit of a cheat by camera manufacturers to make their products seem like they have better noise control than they really do. I don't mind JPEGs with always-on noise reduction but if shooting raw then it should be the unadulterated data coming off the sensor. The problem is partly caused by the kind of obsessive pixel peeping you see in reviews and on websites like dpreview where there's endless moaning about noise when shooting at high ISOs that back in the days of film would have been considered almost unusable and in response manufacturers (not just Sony) have sometimes fiddled the figures. Fuji do it in their higher end X-Trans models (although less aggressively than Sony) which is why I stuck to their cheaper and more basic cameras that use a standard Bayer pattern and produce proper raw files.

You don't have to invest a lot to get good image quality from a camera and there are places like MPB.com which specialised in selling used photo gear and who have a proper returns policy and 6 month guarantee if you'd rather stay away from places like eBay. Something with a similar spec to the A6400 can be had relatively cheaply - the shot below was taken with my £180 eBay special and I think it did a good job for such a basic camera shooting narrowband in H-alpha and O-III. You can put together a very capable kit for a lot less than £2000, especially if you're buying some or all of it secondhand.

2 hours ago, Grumpy Martian said:

I too have always had an interest in the 150 mm achromat at shorter focal ratios. I understand it's limitations. But would still like one for general stargazing. I have an ST 120. The moon looks half decent through it. Saturn shows up well. But Jupiter is a different story.

If you decide to pass,perhaps you would put it a word for me. Bit mercenary I know.lol

How does the false colour in a large achromat compare to what you'd see with something like a small f6 ED doublet?

Do you have a budget in mind?

The most grab and go setup in terms of being ready to use ASAP with little cool down time would be a small refractor. A Mak should be good for the Moon and planets and is a really compact solution, but they're not the quickest to acclimatise.

1 hour ago, Ed Galea said:

Thanks for the welcome and the reference M40.  I'll have a closer look at this thread, but from what I've seen, most of the contributions involve camera and telescope.  For my step 1, I'm focusing on camera and lens only.   This is a huge site so I guess my question has already been answered a dozen or so times!  Just need to find it.  A current camera I'm considering is the Sony A6400 and the lens that many seem to use, the Samyang 2/135mm.  I'm prepared to spend a bit more, so want to get as much camera and lens for my money as possible.

Thanks again for your comment and reference.

The Samyang lens is superb and very highly regarded. I don't have that particular lens but I've got a few other Samyang models and they're all brilliant.

Sony cameras have great sensors but you do need to be careful about their suitability for astrophotography. Sony tend to implement a rather aggressive form of noise reduction which is applied to the raw files themselves and can't be turned off (unless this has changed recently) and it manifests itself by deleting fainter stars from the image, thinking they're actually noise. It's known as the "star eater" bug and it would be worth checking whether it's still an issue for that particular camera.

I'm big fan of mirrorless cameras generally. Their small size, light weight, and short back focus distance makes them a great choice for all sorts of photography, but astrophotography in general. I've got a couple of 24 megapixel Fuji mirrorless cameras which use Sony sensors and are surprisingly good. Different makes and models have their pros and cons and it's not uncommon for cheaper models to be better suited to astro than more expensive ones because they're less likely to have fancy features that you don't need and can't turn off.

You can get great deals by shopping secondhand and there are real bargains to be had in pre-modded cameras that have had their stock filters removed or changed to give them much better red sensitivity and massively improve their performance for astro imaging. My little 24MP full-spectrum modded Fuji only cost me £180 which is less than I'd have to pay to get an existing camera modified.

Gear nowadays is so good that even very low end cameras are far better than what was the state of the art not that many years ago. Cheap kit and putting your efforts into learning the techniques and workflow for astro imaging will deliver far better results than throwing money at the problem but not developing those skills.

I've got an AZ GTi and I can confirm that my FC-76DCU worked absolutely fine on it.

Seems to work even with larger scopes such as the FC-100D models although I would have thought the DF and DZ versions might be pushing it a bit given their weight.

13 hours ago, bond19 said:

Hi Malcolm.

I too am considering changing my 2" diagonal to achieve focus. Can I just clarify is the Badder diagonal you use a 1 1/4"?

I don't know if you've seen this article by William Paulini (BillP) reviewing different diagonals. There's some very useful info about optical path lengths which could be handy in deciding which diagonal to use and it shows prisms having significantly shorter optical lengths than equivalent mirrors as well as a useful comparison of other specifications and features.